Researchers advise the use of anesthesia in fetuses from 21 weeks of gestation

Although the problem of whether fetuses are able to feel pain or not is still controversial, experts at the University Hospital Virgen del Rocío in Seville have recently published a study in which they found that from the second trimester of pregnancy, the future baby already shows signs of pain when given a harmful stimulus or as a response to stress. The finding, the researchers argue, indicates the need to anesthetize the fetus during open fetal surgery, OFS.

There is a school of thought that believes that in the case of fetal interventions, it is sufficient to administer anesthesia to the mother as this passes through the fetus through the umbilical cord. Now, the experts have shown that this might not be sufficient and that from 21 weeks, the fetus can feel pain, so it also needs to be anesthetized.

“At the Hospital Virgen del Rocío, we have spent a decade doing open fetal surgery. In 2007, we did the first intrauterine spina bifida operation in Europe, and in only one case was the fetus unable to receive intravenously administered anesthesia from the start of the operation. It was at that moment that our monitoring teams detected anomalies in the behavior of the fetus, which led us to believe that this was effectively a reaction to the stress caused by the pain. We quickly out in place the anesthesia protocol and the spinal reconstruction was possible and the post-op period passed without any problems,” explains Dr. Javier Márquez Rivas, Heat of the Infant Neurosurgery Unit and the Neurosurgery Service at the hospital.

For her part, Dr. María J. Mayorga Buiza, pediatric anesthetist and first signatory of the article, adds that one of the key aspects of anesthesia in open fetal surgery is to help uterine relaxation, to keep fetal circulation stable and, once surgery is complete, to offer adequate management of the patient to avoid contractions among other complications, which helps to reduce the incidence of premature birth in these cases.

Open fetal surgery (OFS) is still a serious procedure for the mother and the fetus. In such cases, anesthesia given directly to the fetus can be provided by different means, but in the opinion of these experts, direct administration is “obligatory” for reduce fetal stress and also release the incidence of fetal mortality.

Even though current models do not prove the perception of fetal pain before the third trimester and there is little evidence of the effectiveness of direct fetal analgesic and anesthetic techniques, it is a confirmed fact that fetal mortality is higher than 20% in the case of non-anesthetized fetuses. This rate drops to 0% in operations carried out until now at the University Hospital Virgen del Rocío in Seville.

“The response of fetal stress to harmful stimulation that our monitoring teams observed in this case, does not completely prove that the fetus can feel pain. However, it is very improbable that there can be a perception of pain without a response to stress, and so these signals are often used as a substitute pain indicator,” explains the University of Seville researcher and co-author of this study, the Applied Physics professor Emilio Gómez González.

The research team that Prof. Gómez Gonzalez leads works on the development of optical and neurophotonic techniques which are capable of evaluating the state and characteristics of the areas where surgery is taking place during complicated procedures.

“To advance in the area of anesthesia is to advance in surgery. Formerly, there were patients who died from pain, therefore, the better our knowledge and training in anesthesia and the greater the abilities of the monitoring teams, the more complex surgery can be,” states Dr. Mayorga Buiza.